Switch mechanism



June 13, 1939. w. R. CURTISS 2,152,528

SWITCH MECHANISM Filed July 31, 1937 H c J 1-, I a 54 5| I4 {53 I8 :4 l5 T #1 56 42 as I 35 45 44 -43 4 a :ii T, 59 as 30 y 37 47 t m 44 INVENTOR.

27 6 cm W ATTORNEY.

Patented June 13, 1939 UNITED STATES PATENT OFFECE SWITCH MECHANISM ware Application July 31, 1937, Serial No. 156,675

12 Claims.

This invention relates to electrical apparatus and more particularly to switch means for controlling the flow of current in electrical circuits.

One of the objects of the present invention is to provide novel switch mechanism adapted for use in hospital call systems and the like.

Another object of the invention is to provide novel switch mechanism embodying means for releasably and automatically locking the same in operative position whereby release thereof will not be effected by sudden shocks, jarring, or the like.

Still another object is to provide a novel switch for controlling a plurality of circuits which is more simple in construction, less expensive, and more readily constructed than similar devices heretofore employed.

A further object is to provide a novel switch mechanism which is so constructed that the same is more reliable and easier to assemble and disassemble for inspection, cleaning and repair than are similar devices heretofore provided.

The above and further objects and novel features of the invention will more fully appear from the following detailed description when the same is read in connection with the accompanying drawing. It is to be expressly understood, however, that the drawing is for the purpose of illustration only and is not intended as a .30 definition of the limits of the invention.

In the drawing, wherein like reference characters refer to like parts throughout the several views,

Fig. 1 is a sectional view with parts broken 35 away of one form of switch mechanism embodying the present invention, the section being taken in the plane of line |I of Fig. 6;

Fig. 2 is a similar view with the cover piece removed, the section being taken in the plane of 40 line 2-2 of Fig. 6;

Fig. 3 is a view similar to Fig. 1, the section being taken in the plane of line 3-3 of Fig. 6;

Fig. 4 is a detail isometric view of one form of cam element which may be employed in carrying 45 out the invention;

Fig. 5 is a detail sectional view of the main body of said switch mechanism, the section being taken on line 55 of Fig. 2; and,

Fig. 6 is an end view of said mechanism with 50 the cover, cam element and wiring removed, the

view being taken on line 6-6 of Fig. 3.

The single embodiment of the invention illustrated in the drawing, by way of example, is shown in the form of a novel self-locking switch 55 mechanism adapted for use in hospital call systems or the like to enable a patient or other operative to give both visual and audible signals either or both of which may be intermittently or constantly energized. In the form illustrated, said mechanism comprises a housing or body l6 5 of suitable insulating material such as Bakelite,

said body being generally cylindrical with an enlarged portion II at one end thereof. A central or axial bore is provided in body IE3 for the reception of the movable parts of the switch mech- 10 anism and parts adapted to cooperate therewith, said bore comprising a cylindrical portion i2 at the enlarged end of the body, a square portion l3 intermediate the ends of the body and a substantially square portion M With filleted corners, the Walls of said square portions making angles of 45 with each other, as best seen in Fig. 5. The axial lengths of portions l2, I3 and M of the bore through body ID are represented by the distances a, b and 0, respectively, (Fig. 1).

For a purpose to appear hereinafter, that portion of body In containing bore i3 is milled or cut away at the center of each side of said bore to form two pairs of diametrically disposed slots or internal grooves l5, l5 and I6, I 6, the outer surfaces of said grooves being flush with the periphery of bore l2 (Figs. 1 and 2) which is preferably of the same or slightly greater diameter than the small portion of body 10. A plurality of grooves or recesses are also milled in the outer surface of that portion of body H1 in which bore l3, I4 is located, two of said grooves I7, I! (Fig.

2) being in alignment with slots l6, l6 and connecting therewith. A third groove l8 (Fig. 1) is provided in alignment with one of the slots 15 and diametrically disposed with respect to groove I8 is a short semi-circular groove or recess l9. Spaced about the periphery of body l9 and interposed between the grooves I! to l9 are four equally spaced external grooves 253 which extend 0 a short distance from the left end of body 10,

as viewed in the drawing (Fig. 3). Radially inward from grooves 20 are four internal grooves 21, Zls cut in the inner wall of bore I4, each of said latter grooves being centrally disposed in a side wall of said bore and one of said internal rooves 2ls being axially shorter than the other three (Fig. 3). Grooves 20 and 2|, 2|s are joined by slots in the end of body In for the reception of U-shaped or hook-like conductors 22, 22s, to be more fully described hereinafter.

A U-shaped guide member 23 which also functions as an electrical conductor, in a manner to hereinafter appear, extends into bore I3 and is held in position by one or more stud bolts 24 which freely extend through the wall of body l0 (Fi 1) and threadedly engage said guide member. Said member 23 is provided at one end thereof with diametrically disposed ears 25, extending therefrom at right angles and into slots or grooves I5, 15.

Slidably extending through an opening in the inner end or cross bar of guide member 23 and having electrical contact therewith is a recipro cable spindle 26 of conducting material, the outer reduced end of which is threaded for receiving a push button 21 of suitable insulating materiali such as Bakelite. Interposed between button 2 1 and a shoulder on spindle 26 is an element 28' which has radially projecting portionswhich slidably extend into slots I6, 16"(Fig. 2). Element 28 is preferably fixed against rotation on spindle 26 by providing an elongated slot in said'elernent for receiving a correspondingly cut portion ofsaid spindle. Suitable resilient means, such as a coil spring 29,interposed between the crossbar of member 23 and element 28 are provided iornore mally urging spindle 26, 2lto. the right, as'viewe'd in the drawing,the movement of spindle 26 by the spring beinglimited by a collar 36 on the spindle which is adapted to engage the inner'end of member23.- 1 H Mounted-on the inner end of spindle26iisa contact member provided with'a plurality oiresilient contact fingers 32, eachof saidfingers being-adapted to engage one of the hock-likecon ductors22, 228 which fill internal-groovesll, 2 Is, and are flush with the fiat inner surfaces of bore l l-(-Fig.' 3). Fingers 32 are formed froni' asingle blank of thin resilient material which; in the form shown, is secured to spindle 2$ by providing a central opening in said blank and peening over a hollow tube-like portion33' provided on the end of spindle 26. I To hold fingers: 32 against; rotation relative to spindle 2t, a laterally extending portion or tongue 36 of the contactumember is benti-nt'o a slot formed in collar (Fig; l) The lengths-of fingers 32 and'the lengths of the internal portions of 'conductors'22 are such-that, when spindle 26, His in its extreme right-hand position with collar 3ll engagingimember 23,'-there will :be no'engagement of said fingersand conductors with each other. When button 21 is pushed L inwardly, -however. to the intermediate position illustrated in Figs. 1 and 2, three'oi :the 'fingers' 32 move into electrical engagement with the three conductors 22, while the finger corresponding to conductors 22s remains inf contact with the walls of insulating-body Hi. Upon-fur ther depression ot'button 27-, theshort'conductor -22s is;enga'ged-by-one of thefingers' 32, while the other' three of-said'fingers are bent inwardly and out of electrical contact with conductors 22 i by novel cam means tobe next described (Fig; 3);

Said novel cam -means, in theform illustrated,

are constituted by an insulatingdisc-like member 35 (Fig- 4) The member-35 may-be provided with a positioning-lug to extend into groove I9 of the body Preferably,--thesaid member is adapted-tobe secured to theendof body' lfii by one or more screws 36 which threade'dly eng'age radially andinwardly extending-portions of a 'pair'of metallic strips 31/3! which are; in turn, fixedly securedin grooves I l, 'l-lby'stud bolts 38, 38 that threadedlyengage-the walls *ofbody 19 (Fi 2). Formed integrally with or rigidly secured to the inner faceof disc 35 are three cams 39 each: having a flat surface adapted toengage one of the flat walls of bore l4 and partially cover an internal portion of a-conductor*22'-and each three of the contact fingers 32 will engage condubtors 22 and establish circuits which will remain closed until the spindle is released by the operator through the operation of suitable means ftobe hereinafter described. The novel construc- 'tion :of .the switch mechanism heretofore described permits the provision of holding means which obviate the danger that spindle 26, 2": will #bereleasedwhen said mechanism is dropped or subjected to some other shock or jarring of some nature. comprise apair of diametrically disposedleaf springs, .40 secured in grooves ill? by strips 31 and studs 38 (Fig.112) and so shaped as to provide. ashoulder M adapted to. engage the upper .surfaces-ofthe ends of element when spindle 26,121 is in an'Jintermediate position. It will beseen that, by employing two diametrically opposed springs lil, any tendency to jar'one of said: springs to such position as to release spindle 26,-'21.will tend to urge the othertoward its hold.-

ing position. a a

Novel means are also provided for releasing spindle 26,- 21 when the sam is being held in intermediate position by springs GB, said means,

as shown; comprisingan annular button 32 of insulating material which has a sliding fit in bore I2 and surrounds button 21- A pair of bevelled lugs 43f43 -(Fig, 2)' are mounted on or formed integrallywith the inner face of button -52 in alignment with grooves I 6- and springs M5. When button 42 is pressed inwardly; the bevelled outer faces of lu'gs 43-are adapted to engage the outwardl-y turned ends of springs iii and thereby move the latterin diverging directions to move 'shoulders l'lbeyond the ends of member 23 and release spindle-26, 21 for moveinentto inopera tive: positionby spring 29. Button -12 may be guided. and held against-'rotation by a pair of inwardly extending pin's M which slidab-ly ex-- tend through openings in the laterally extending ears 2 5 of guide member 23 (Fig. 1)'. 7 Any suitable resilient means, such as coil springs 5 interposed between cars 25 and button 42, maybe provided for normally holding --the latter out of contactwith sprin'gs-dwhe movement of said yond-the-periphery of body'll'l and wires 58 pass through notches fificut in the" periphery of disc 35.-'-It be here noted that -eitherbolts 49 or disc 35 is '-effective to maintain contacts. 22, 228

In the form shown, said holding means imposition and against removalfThe fifthwire W trical energy (not shown) and to a conductor plate 52 by a stud bolt 53 that is threaded into said plate, the latter being held in position in groove l3 and electrically connected to guide member 23 and, hence, to spindle 25 by bolt 24 (Fig. l). The other terminals of the signals and source of energy above referred to may be connected together by any suitable means, such as through suitable ground connections.

In order to obviate any tension on the individual wires 48 and 5| and on the terminals to which said wires are connected, a disc 54 having a central opening therein may be provided on cable i! and secured to disc-like member by means of screws (Fig. 1). Wires 48, 5! are thus firmly clamped between members 35 and 54.

To protect the switch mechanism against dirt, moisture, and the like, a cover 56 is provided therefor. Said cover, in the form shown, is cylindrical, the inner diameter thereof being slightly greater than the outside diameter of body iii. Said cover is provided at one end with a small opening through which cable 41 slidably extends and is internally threaded at the other end for threaded cooperation with threads 51 cut on the periphery of body l0 adjacent the enlarged portion thereof. Cover 56 is shown in installed position in Fig. 1.

In operation, when button 21 is pressed in- \vardly a sufficient distance to cause fingers 32 to contact conductors 22, circuits will be closed from the source of energy through wire 5!, plate 52, bolt 24, guide member 23, spindle 26 and three each of contact fingers 32, conductors 22 and wires 48 to three suitable signals (not shown) which may be either visual or audible or both and located at the same or different stations. With button 2i in this position, springs 45 snap inwardly so that shoulder M engages the ends of element 28 thereby automatically and releasably locking spindle 26, 2'! and contacts 32 in an intermediate and operative position, i. e., the position illustrated in Figs. 1 and 2. In the usual hospital call system, the three conductors 22 are connected in circuit with visual signals and conductor 22s is connected in circuit with an audible signal. When it is desired to energize said audible signal with the above-described switch mechanism, button 21 is pressed inwardly beyond said intermediate position until one of the fingers 32 engages conductor 22s and the other of said fingers are lifted out of contact with conductors 22 by cooperation with cams 39. The visual signals connected to the latter conductors are thus deenergized until spindle 26, 21 is permitted to return to intermediate position, i. e., by removing the pressure from button 2?. Thus, by repeatedly pressing and releasing button 2?, intermittent visual and audible signals may be given. It will also be seen that by eliminating one or more of the cams 39, a signal may also be constantly energized even when button 2? is reciprocated. Additionally, it will be noted that, once button 2'! has been pressed to energize a signal, the same will be held in operative position by springs 48 until released by depression of button 42 while spindle 26, 21 is free to be moved outwardly by spring 29. Upon depression of button 42, the bevelled lugs 43 thereon engage the upper ends of springs 45, thereby spreading the same and releasing spindle 26, 2'! for movement to inoperative position. This latter operation is ordinarily performed by the nurse after the signal given by the patient has been answered.

There is thus provided a novel switch mechanism for controlling a plurality of signal circuits whereby intermittent or constant audible or visual signals may be given in a variety of combinations. The mechanism is extremely simple in construction, the same embodying only a. small number of rugged, compactly assembled parts which may be inexpensively manufactured and which are readily assembled and disassembled for inspection, cleaning, and repair. The mechanism provided is so constructed that it is only necessary to thread two set screws into the Bakelite body, thereby materially increasing the l fe of the device, said two screws being ones which need not be removed in the usual disa sembly for cleaning or repair.

Although only a single embodiment of this invention is illustrated and described, it is to be expressly understood that the same is not limited thereto but that various changes may be made therein, particularly in the design and arrangement of parts illustrated, without departing from the spirit and scope of the invention, as will now be understood by those skilled in the art. For a definition of the limits of the invention, reference is had primarily to the appended claims.

What is claimed is:

1. In apparatus of the class described, a tubular insulating housing, a hook-like conductor engaging the inner and outer walls of said housing at one end thereof, reciprocable means in said housing including a resilient contact member adapted to engage the portion of said conductor which extends into the bore of said housing, resilient means coasting with said reciprocable means for normally holding said contact member in a limiting position out of engagement with said conductor, means for releasably holding said reciprocable means against movement by said resilient means after movement of said reciprocable means to intermediate position with said contact member in engagement with said conductor, and means mounted at the end of said housing and having a portion projecting into the bore thereof for lifting said contact member out of engagement with said conductor when said reciprocable means is moved beyond said intermediate position.

2. In apparatus of the class described, a tubular housing, a pair of reciprocable concentric buttons in one end of said housing, a guide member rigidly secured in said housing, resilient means interposed between each of said buttons and said guide member, means carried by each of said buttons adapted to slidably extend through said guide member and to engage the latter for limiting the movement of said buttons by said resilient means, a pair of diametrically disposed springs mounted on said housing, means carried by one of said buttons adapted to be engaged by said springs to hold said button in depressed position, and means on the other of said buttons for moving said springs to inoperative position.

3. In apparatus of the class described, an insulating housing having a bore therein, a conductor slidably extending into a recess at one end of said housing, conductor-securing means including a terminal-member threaded into said conductor and freely extending into an opening in the wall of said housing for holding said conductor in position, and a reciprocable contact member in said housing adapted to be moved axially of the latter into and out of yielding engagement with said conductor.

4. In apparatus of the class described, an insulating housing having a bore therein, a conend of said housing, conductor-securing means inoludinga terminal-member threaded into said 1 conductor and freely extending into an opening in the Wall of said housing for holding said conductor in position, a reciprocable' contact memberin said-housing adapted to be moved axiallyof the latterinto and out of yielding engagementwithsaid conductor, resilient means for locking said recprocable contact in position to engage said conductor, and means for releasing said resilient locking means.

5. In apparatus of the class described, a housing having a bore therein, a plurality of fixed conductors in said bore and extending to the end thereof, reciprocable means in said housing including a plurality. of resilient cont-act fingers adapted to yieldingly engage the wall .of said bore and said conductors, and insulating means mounted on and closing the end of said housing and having. aportion extending into said bore for moving said contact. fingers out of engagement with, certain of-said conductors in response to movement of said fingers axially of said bore.

6- In apparatus: of the class described, an insulating housing having av bore therein, a plurality of peripherally spaced, U-sh-aped conductors slidably engaging the inner and outer Walls of'said housing, conductor-securing means including a disc-like member across the end of said housing, the said disc-like member engaging portionsof the. said plurality of, conductors to hold saidconductors in mounted position, and a reciprocablecontact member in said housing adapted to be moved axially of the latter into and out of yielding engagement with said conductors.

7. In apparatus of the class described, a housing of insulating material having a bore therethrough, said housing having an external groove andv an internal groove adjacent one end thereof, said grooves being radially disposed with respect .to each other, a hook-like conductorwith portionsthe'reof slidably fitting into said grooves, removable means for normally holding said conductor in .said grooves, and means slidably mounted in said bore including a resilient contact adapted to alternately engage the portion of thesaid conductor extending in the said internal groove and to also engage the wall of said bore upon reciprocation. of .saidlast named means axially. of said bore. 7

8. In apparatus of the classdescribed, an insuIati-nghousing having a bore therethrough, said housing having a plurality of peripherally spaced external grooves at one end thereof .and a plurality of internal grooves in the surface of said bore, each ,of said internal grooves .being radially disposed with respect to one of said external, grooves,,a plurality of hook-like conductors each -havinga portion thereof slidably extending intooneofsaid external grooves and a, portion slidably extending into a corresponding one of said internal grooves, common means for holding all of the said conductors in position in said grooves, and means slidably mounted in said bore including a plurality of resilient contacts adapted to yieldingly and successively engage the wall of said bore and the portions of said conductor extending into said internal grooves when said slidably mounted means are reciprocated axially of said bore.

9. In apparatus of the class described, a'housing of insulating material having a bore there through, said housing having an external groove and an internal groove at one endv thereof, .said grooves being radially disposed with respect to each other, a, hook-like conductor with portions thereof slidably fitting into said grooves, an insulating member for holding said conductor in position in said grooves, said member having a portion extending into said bore and partially covering the portion of said conductor in said internal groove, an element slidably mounted in said bore, and a resilient contact mounted on said element and adapted to successively engage the wall of said bore, said conductor and said extending portion of said, insulating member;

10. In apparatus of the class described, 311111? sulating housing having a bore therein, said housing having an external groove and internal groove at one end thereof, said grooves being radially disposed with respect to each other, a hook-like conductor with portions thereof slidably, fitting into said grooves, and conductorsecuring means including a terminal-member threaded into the portion of said conductor in said external groove, said "means extending through said conductor and'into a recess in said housing for holding said conductor in position on the latter. a a

11. In apparatus of" the class described, an insulating housing having a bore therethrough, said housing having axially extending internal and external grooves connected by a radially extending groove at the inner end of said housing, a hook-like conductor slidably fitting into said grooves, and conductor-securing means including a disc -like member engaging said end of the housing and the portion of the conductor in the radially-extending groove for holding said conductor in position in said groove, and the said dis'c-likemember also closing the said bore at the inner end of the housing. V

12. In apparatus of the class described, an insulatinghousing having a bore therethrough, said housing having an axially extending internal groove in the end of said housing, a hook-like conductor slidably fitting into said groove, and

means engaging said end of the housing for holding said conductor in'position in said groove, said holding means having an insulating portion extending into said bor'e and partially covering the part of said conductor in said internal groove.

WILLIAM R. CURTISS. 

